1. Field of the Invention
The present invention relates to a resistive random access memory and a method for producing the resistive random access memory and, more particularly, to a resistive random access memory with an oxygen concentration difference and a method for producing the resistive random access memory.
2. Description of the Related Art
Memories have been widely used in various electronic products. Due to the increasing need of data storage, the demands of the capacities and performances of the memories become higher and higher. Among various memory elements, resistive random access memories (RRAMs) have an extremely low operating voltage, an extremely high read/write speed, and highly miniaturization of the element size and, thus, may replace the conventional flash memories and dynamic random access memories (DRAMs) as the main stream of memory elements of the next generation.
FIG. 1 is a diagrammatic view of a structure of a conventional resistive random access memory 9. The conventional resistive random access memory 9 includes two electrode layers 91 and a resistive switching layer 92. The resistive switching layer 92 is located between the two electrode layers 91 to form a metal/insulator/metal (MIM) structure. The oxidation/reduction reaction of the metal filaments M in the resistive switching layer 92 can switch the resistive switching layer 92 between a low resistance state (LRS) and a high resistance state (HRS) for storing two logic states (such as 0 or 1).
When the two electrode layers 91 are supplied with electricity, although the resistive switching layer 92 possesses the resistive switching characteristics, the electric field is not uniformly distributed among the dielectrics such that the conductive path formed by the resistive switching layer 92 is unstable, leading to unstable characteristics of the resistive random access memory element while failing to reduce the power consumption.
Thus, improvement to the conventional technique is required for enhancing the utility.